782 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



f. 18. Brackisli water. Europe, Asia, 

 Australia, and America, (iv. 21.) 



N. specfabilis (E.). — Large ; front view 

 broadly linear, with truncated cuneate 

 apices ; valves with rounded ends. = 

 Synedm spectahilis, EA. and M, several 

 figures. Europe, Asia, Australia, Africa, 

 and America. The valves are figured as 

 elongated, narrow linear, with suddenly 

 attenuated, obtuse, reflected apices, and 

 a row of puncta on one margin. 



N. insic/nis (Greg.). — Front view 

 broadly linear, with rounded ends and 

 conspicuous marginal puncta and striae ; 

 valves linear lanceolate, straight or 

 slightly sigmoid, with subcentral keel 

 and 30 distinct striae in -001". Greg. 

 MT. V. pi. 1. f. 46. Marine. Scotland. 

 Distinguished from N. sigmoidea and N. 

 Brchissomi by its straight front view; 

 and from N. scalaris by its finer markings, 

 more slender form, and nondilated ends. 

 Greg. 



N. gigcmtea (E.). — Very large, linear, 

 with suddenly rounded ends ; valves 

 \\\ih. attenuate subacute apices ; surface 

 finely striated in the intervals of the ^\n- 

 nu[es. = Sgnedra qiqantea, ERBA. 1841, 

 p. 22; Synedra^ Lihgca, KSA. p. 48. 

 Oasis of Jupiter Amnion, 1-60". 



N. linearis (Ag., S.). — Front view 

 linear, with rounded or truncate apices 

 and nearly central keel ; puncta in a 

 single row; striae obscure. SBD. i. p. 

 39, pi. 13 & pi. 38. f. 110. = Frustidia line- 

 aris, Ag. Fresh water. Europe. 



N. Pcdea (K., S.). — Front view linear ; 

 valves narrow, lanceolate, acute. SBD. 

 ii. p. 89.=Sy?iedra Palea, KB. p. 63, t. 4. 

 f. 2 ; Synedra Fusidimn, KB. p. 64, t. 30. 

 f. 33 ; Syiiedra fusidioides, Bab D. p. 53, 

 t. 4. f. 47. Europe. Frustules minute. 



N. tenuis (S.). — Front view linear, 

 truncate ; valves narrow, lanceolate, 

 acute ; striae obscure. SBD. i, p. 40, pi. 

 13. f. 111. Fresh water. England. 



2t Extremities, in front view, with a 

 hyaline wing or expansion on each side. 



N. spathulata (Breb.). — Front view 

 lanceolate, with the truncate ends dilated 



on each side ; valves lanceolate acute, 

 with a single row of puncta. SBD. i. 

 p. 40, pi. 31. f. 268. Marine. France 

 and England. 



N. distans (Greg.). — Front view broad, 

 sublinear, with distant irregularly dis- 

 posed marginal puncta; apices truncate 

 with a slight hvaline expansion on each 

 side. GDC. p. 58, pi. 6. f. 103. Marine. 

 Scotland. Valves lanceolate, with acute 

 apices and central keel. 



N. hyalina (Greg.). — Front view sub- 

 linear, with small, regular marginal 

 puncta ; valves narrow linear, with con- 

 tracted, produced apices and central keel. 

 GDC. p. 58, pi. 6. f. 104. Marine. Scot- 

 land. Keel apparently double ; but per- 

 haps one is seen through the very hyaline 

 valve. Greg. 



3 t Front view lanceolate. 



N. angidaris (S.). — Front view rhom- 

 boid-lanceolate, truncate ; valves lanceo- 

 late, with central keel ; puncta in a single 

 series and longitudinal lines. SBD. i. p. 

 40, pi. 13. f. 117. Marine. Sussex. 

 This and the following species ought 

 perhaps to be placed in Ceratoneis. 



N. lanceolata (S.). — Front view broadly 

 lanceolate, acute ; valves lanceolate, ros- 

 trate, acute, with eccentric keel and 

 longitudinal lines. SBD. p. 40, pi. 14. 

 f. 118. Marine. Sussex. 



Douhtfid or insufficiently described Species. 



N. valens (E.). — Very large, broadly 

 linear, finely striated, with trimcate ends. 

 = Synedra valens, EA. t. 3. 2. f. 6. Fresh 

 water, (xii. 44.) Mexico and United 

 States. 



N. curvula (K.). — Elongated, curved; 

 front view slightly attenuated towards 

 the truncate apices ; valves acuminated, 

 subacute, sometimes with a longitudinal 

 punctate line. = Synedra curvula, KB, 

 p. 65, t, 15. f, 2. Fresh water. Prussia. 

 1-240". 



N. JEhrenberc/ii = Synedra amphilepta, 

 EM, pp. 34-5, *£ 11. CapeVerd. Elon- 

 gated, straight, linear, with striated mar- 

 gins and acutely cimeate apices. 



Genus CEBATOl^EIS (Ehr.).— Frustules as in Mtzschia, but with long 

 rostrate ends, and usually with a more or less evident central pseudo-nodule. 

 Professor Smith, after excluding some of its species, made Ceratoneis a sec- 

 tion of Nitzschia, and perhaps was justified in so doing ; but as the forms 

 included in it are remarkable for their fidiform beaks, and there is some 

 appearance of -a central nodule, we have retained the genus, at least for the 

 present. Some of the species resemble the Closteria in form, and have been 

 referred to as showing an affinity between the Diatomaceae and the Desmi- 

 diea?. The resemblance, however, is merely superficial, and, instead of showing 



